1. Field
This invention pertains to golf club shafts, golf clubs, and methods for producing them. More particularly, it pertains to a nodal controlled kick-point lightweight golf club shaft for attachment to a lightweight golf club head made of titanium or other lightweight materials of similar or lessor density, and a method to produce the same.
2. State of the Art
Numerous lightweight golf club shafts and golf clubs are known. Conventional golf club drivers have heads weighing approximately 200-210 grams. In comparison, the newer lightweight titanium golf club drivers have heads weighing approximately 180-190 grams and require a lighter weight golf club shaft to lower the center of gravity of the club to provide better swing balance. Present lightweight golf club shafts are made of hollow tapered steel, which weigh approximately 120 grams, or hollow tapered graphite, which weigh approximately 95 grams. Czeck, U.S. Pat. No. 4,157,181 is an example of a typical narrow diameter graphite fiber tapered shaft having a handle end onto which are slid solid pre-wrapped and capped one-piece handles weighing approximately 46 to 52 grams. Inouet et al, U.S. Pat. No. 3,998,458 is another example of a typical narrow diameter graphite fiber tapered shaft generally having a dimension of 6 to 9 mm in diameter at the tip portion, and a 14-17 mm in diameter at the shaft butt portion onto which a solid one piece handle is inserted thereon. These solid one piece handles act to shift the center of gravity of the club toward the handle end; thus giving an unbalanced feel which also does not concentrate the weight of the club in the club head, during the swing.
Also, the flex of present graphite shafts is not adjusted to match the club head striking characteristics. Traditional wood and club head designs prevented the shaft from being located closer to the sweetspot (the clubheads' center of gravity). Thus anything less than a dead center impact caused the shaft, especially early graphite shafts, to over-torque, causing directional problems and less-than-perfect feel. To counteract this, graphite shafts had to be designed with stronger, heavier materials. This produced a stiffer, less-responsive shaft and a decrease in distance and feel, particularly for off-center hits.
In addition, the clubhead was not matched to the shaft's flexing characteristics. The easiest way to design a solid feeling, more forgiving clubhead is to drop the center of gravity very close to the sole of the club. This increases the amount of backspin, causing the ball to climb higher. Although this is effective, the trade off was a loss of forward momentum and excessive shot trajectory. High, short shots became the trademark of the standard metal wood design.
Newer 55-60 gram hollow graphite shafts, the solid one piece handles are even more top heavy, and accentuate the unbalanced feel. There therefore remains a need for a new shaft, club, and handle design to control the shaft torque and flex and concentrate the weight of the club in the club head to provide an optimum pendulum striking effect. The invention described below, provides such an improvement and method for making the same.